<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title></title>
    <script src="browser.js" charset="utf-8"></script>
    <script type="text/babel">
    let a=12;
    let b=5;

    alert(a+b);
    </script>
  </head>
  <body>

  </body>
</html>
